TB-500 impurity profile
Every named species the index has reported alongside TB-500, how often, at what level, and what its presence implies about the synthesis or the handling. Reporting threshold is 0.05 % area; anything below it is invisible to this page and is silently added to the main peak.
Median total impurities
0.53%
n=356
Median largest single
0.26%
n=356
Worst single observed
1.77%
n=356
Named species observed
4 / 4
n=4
| Named species | ΔRT (min) | Δ mass (Da) | Seen in | Median % area | Max % area |
|---|---|---|---|---|---|
| C-terminal amide (−1 Da) | +0.18 | -0.984 | 91% | 0.10 | 1.54 |
| des-acetyl TB-500 (−42 Da) | -0.52 | -42.011 | 88% | 0.11 | 1.11 |
| des-Gln truncate (−128 Da) | -0.24 | -128.059 | 87% | 0.09 | 1.77 |
| [D-Thr]-diastereomer | -0.11 | mass-identical | 85% | 0.10 | 1.51 |
C-terminal amide (−1 Da)
- Retention offset from the main peak
- +0.18 min on RG-2
- Mass difference
- -0.984 Da
- Reported in
- 325 of 356 records (91 %)
- Level when reported
- median 0.10 %, max 1.54 %
- Resolution requirement
- Close-eluting — resolution below 1.2 is common and the peaks merge on short gradients.
des-acetyl TB-500 (−42 Da)
- Retention offset from the main peak
- -0.52 min on RG-2
- Mass difference
- -42.011 Da
- Reported in
- 314 of 356 records (88 %)
- Level when reported
- median 0.11 %, max 1.11 %
- Resolution requirement
- Baseline-resolved on the reference method.
des-Gln truncate (−128 Da)
- Retention offset from the main peak
- -0.24 min on RG-2
- Mass difference
- -128.059 Da
- Reported in
- 309 of 356 records (87 %)
- Level when reported
- median 0.09 %, max 1.77 %
- Resolution requirement
- Close-eluting — resolution below 1.2 is common and the peaks merge on short gradients.
[D-Thr]-diastereomer
- Retention offset from the main peak
- -0.11 min on RG-2
- Mass difference
- mass-identical — chromatography only
- Reported in
- 301 of 356 records (85 %)
- Level when reported
- median 0.10 %, max 1.51 %
- Resolution requirement
- A gradient long enough to separate it. No mass spectrometer will.
Degradation pathways
Degradants are a handling finding rather than a synthesis finding. A lot that shipped clean and arrived oxidised tells you about the courier, not the chemist.
- acetyl loss under acidic hydrolysis
- no oxidative liability